Brake shoe with venturi cooling passages



June "5, 1956 R. w. FOSTER BRAKE SHOE WITH VENTURI COOLING PASSAGES Filed Jan. 14, 1952 f P.Il. 1

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BRAKE SHOE WITH VENTURI COOLING PASSAGES Robert W. Foster, Sullivan, Ind.

Application January 14, 1952, Serial No. 266,257

6 Claims. (Cl. 18S-261) This invention relates to an air cooled brake shoe, and more particularly to a shoe construction having air grooves formed therethrough for cooling purposes.

This invention is an improvement over and a continuation-in-part of my co-pending application bearing Serial No. 150,079, tiled on March 16, 1950, now abandoned and entitled Air Cooled Brake Shoe, and my co-pending application Serial No. 190,970 led October 19, 1950, and entitled Air Cooled Brake Shoe.

Y It is the primary object of this invention to provide air grooves that are so constructed and arranged as to lengthen materially the life of a railway brake shoe. It is, of course, well known that the friction of a brake shoe against the wheel of a railway car generates a tremendous amount of heat. As a result the shoe tends to develop flaws in certain spots while small slivers form on the braking surface of the shoe. Since the slivers will eventually fuse together there is in time a natural reduction of the contact area between the shoe and the wheel. In addition, the heat generated by friction in the conventional brake shoe is such that the metal plate of arcuate contour that is used to provide anchoring means for the brake shoe is softened thereby. As a result it tends to bend or to expand. Upon cooling the plate contracts. As a consequence of the varying stresses and strains upon the plate there is an accompanying stress and strain upon the brake shoe. As a result the casting ultimately cracks or breaks. There are known instances where a train or a particular car thereof has been derailed by the falling of a portion of the brake shoe or of its clamping plate.

With applicants invention the heat generated by the friction is dissipated sorapidly and to such an extent that the aforementioned diiculties and dangers are substantially reduced if not entirely eliminated. The construction and arrangement of the air passages called for in the abovementioned co-pending applications have proven to be eminently satisfactory for the intended purposes. However, the modifications disclosed and taught in this application have been proven to be a `substantial improvement thereover. It is a further object of the present invention to provide means for cooling the wheels of a railway car in addition to the brake shoe, during braking operations. This is accomplished through the particular location and conformation of the air grooves which are formed in the peripheral surface of the shoe.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

In the drawings Fig. 1 is a side elevation view of a railway wheel with the braking shoes and their supports shown in braking relation to the wheel.

Fig. 2 is a top plan View of the brake shoe.

Fig. 3 is a section view of the shoe taken on lines 3-3 of Fig. 2 in the direction of the arrows.

Fig. 4 is a transverse section View of a brake shoe taken on lines 4 4 of Fig. 3 in the direction of the arrows.

nited States Patent Ov 2,748,903 Patented .lune 5, 1956 ICC Fig. 5 is a bottom plan view of the brake shoe showing my new and improved air grooves.

Fig. 6 is a modified view thereof with parts broken away.

In the drawings, the truck of a railway car is indicated at 10. Pivotally secured to the truck at 11 and depending therefrom on opposite sides of the car wheel 12 are the links or hangers 13. Pivotally carried by the links adjacent their lower extremities are the brake shoe holders 14.

The brake shoe is Shown generally at 15 in Fig. l in braking engagement with the wheel riding on the track 16. The shoe is of conventional contour, i. e. arcuate, and has a pair of opposed lugs 17 projecting upwardly at its extremities. Sockets are formed in the lugs to receive therewithin the ends 18 of the holders.

It is, of course, essential that the shoe be securely connected to the holder. For that purpose there is provided the clamp or hanger 19 through which a pin 20 of the holder extends. This clamp is transversely disposed relative to the shoe and is located medially of the ends thereof.

In order to assure that the clamp is firmly anchored to the shoe, applicant provides not only the arcuate plate member 21 having central cutout portions 22, but as well utilizes the expanded metal elements or mesh 23. The mesh also has central cutout portions complementary to those formed in the plate. In applicants co-pending application Serial No. 190,970, tiled October 19, 1950, and entitled Air Cooled Brake Shoe, the details of the arrangement of the mesh were particularly spelled out.

In order to provide for an air cooling of the brake shoe there are provided the venturi type air passages 29 extending longitudinally of the shoe. Transversely disposed air passages 30 are also provided for further air cooling purposes, and these intersect with the longitudinally disposed passages. Air canopies or scoops 23 are provided at either end of the longitudinal passages, and immediately thereabove, to channel and direct the air into the passages.

Experience has proven that additional air cooling means are desirable in order to assure that the wearing surface 31 of the shoe is adequately cooled. To that end longitudinally disposed grooves 32 are formed in that face of the shoe that confronts the wheel. These grooves are preferably of venturi type. When the shoe is in braking contact with the periphery of the wheel, the grooves become closed passages. Not only does air which is channeled through these passages serve to cool the brake shoe itself but as well the wheel of the railway car. As a result there is not only less wear upon the shoe but also upon the wheel. The air scoops 28 direct air not only into the air passages 29 but also into the grooves 32 which, as aforementioned, become closed passages during the braking operation.

A modication of the air grooves is shown in Fig. 6 of the drawings. The grooves 33 in that ligure are of serpentine or sinuous contour as shown. In order to make sure that there is no sacrifice of gripping surface between the shoe and the wheel, the grooves 33 are so formed that the vale portions 34 of one side of the grooves extend inwardly to a point in the same longitudinal plane as the vale portions 35 of the opposite sides of each groove. In other words, if a longitudinal line 36 is drawn through the grooves medially of their end width, it will touch both the vale portions 34 and the vale portions 35. As a consequence of this construction and arrangement every portion of the wheel will be contacted as it turns by the side walls of the brake shoe defining the grooves. By reason of the serpentine contour of grooves 33 the area of the Wheel and the shoe actually cooled is greater than is the area cooled through the use of the grooves 32. Furthermore, any grit or dirt that is picked up by the wheel will automatically be cleaned therefrom by the side walls defining the sinuous grooves. This construction itself reduces wear for the reason that it removes any abrasives which would other wise tend to increase and accelerate the wear of both the wheel and shoe. The sinuous er serpentine grooves may be of venturi type in order to increase the rate of ow of air therethrough. This means that the cross section of the groove at 37 is less than the cross section at 38 at cach open end. The mesh 23 may be disposed perpendicularly relative to the shoe rather than horizontally thereof when the serpentine type grooves are used.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character', it being understood that only the preferred embodiment and one variation thereof have been shown and described and that all changes and modifications that come within the spirit of the invention and the scope of the claims are also desired to be protected.

The invention claimed is:

l. A brake shoe for use with railway wheels and the like comprising an elongated generally arcuate brake shoe body adapted to conform generally to the contour of the wheel with a wheel engaging and confronting surface and a plurality of longitudinally extending grooves formed in the wheel confronting surface thereof, the inner arcuate wall of each groove being uninterrupted so that each groove will form a closed passage with the wheel when the brake shoe is in engagement with it, the passage being open only at it ends, each groove having a venturi therein.

2. A brake shoe for use with railway wheels and the like comprising an elongated generally arcuate brake shoe body adapted to conform generally to the contour of the wheel with a wheel engaging and confronting surface and a plurality of transversely spaced longitudinally extending venturi type grooves formed in the wheel confronting surface, the inner arcuate wall of each groove being uninterrupted so that each groove will form a closed passage with the wheel when the brake shoe is in engagement with it, the passage being open only at its ends.

3. A brake shoe for use with railway wheels and the like comprising an elongated generally arcuate brake shoe body adapted to conform generally to the contour of the wheel with a wheel engaging and confronting surface and a plurality of longitudinally extending transversely spaced serpentine grooves formed in the wheel confronting surface thereof, the innermost extending portions of the side walls defining one side of said grooves lying in longitudinal alignment with the innermost portions of the side walls defining the other side of said grooves, the inner arcuate wall of each groove being uninterrupted so that each groove will form a closed passage with the wheel when the brake shoe is in engagement with it, the passage being open only at its ends, and air guide means disposed at opposite ends of said shoe adjacent said grooves and extending beyond the ends of the shoe.

4. A brake shoe for use with railway wheels and the like, comprising an elongated generally arcuate brake Shoe body adapted to conform generally to the contour of the wheel with a wheel engaging and confronting surface, at least one groove formed in the wheel confronting surface, the inner arcuate wall of the groove being uninterrupted so that the groove will form a closed passage with the wheel when the brake shoe is in engagement with it, the passage being open only at its ends, each groove being substantially curvilinear and having a reduced cross section therein generally intermediate its ends, the innermost extending portions constituting one side of the groove lying along the saine general longitudinal axis as the innermost extending wall portions de tining the opposite side of the grooves, at least one addi tional air channel in the body of the brake shoe in communication with the wheel confronting surface having openings at opposite ends of the shoes, a plurality of lateral passages in general alignment with the said air channels opening through the sides of the shoe, an air detiecting and guide means disposed at opposite ends of the brake shoe body adjacent the ends of all passages and extending beyond the ends of the shoe.

5. The structure of claim l in which each groove is substantially straight longitudinally, as viewed from the wheel engaging and confronting surface of the shoe, but is arcuate, in cross section when 'viewed from either side of the brake shoe body.

6. The structure of claim l in which the venturi in each groove is located approximately mid-way between the ends of the groove. i

References Cited in the tile of this patent UNITED STATES PATENTS 548,939 Whitcomb Oct. 29, 1895 819,762 Keefe May 8, 1906 886,694 Gibbs May 5, 1908 943,995 Reid Dec. 2l, 1909 1,498,983 Schmidt .lune 24, 1924 1,715,806 Wersall June 4, 1929 1,818,100 Shields Aug. l1, 1931 1,974,905 Walker Sept. 25, 1934 2,026,733 Fast Jan. 7, 1936 2,369,328 `Watts Feb. 13, 1945 2,406,067 Eurit Aug. 20, 1946 FOREIGN PATENTS 488,382 Great Britain July 6, 1938 518,572 France June 6, 1921 

